Method of manufacturing a semiconductor device and a method for fixing the semiconductor device using substrate jig

ABSTRACT

The present invention relates to a method of manufacturing a semiconductor substrate including the back grind step, the dicing step, the pick up step, and the die bonding step of the wafer; and to a semiconductor substrate jig used in such method. The object of the present invention is to mitigate the effect and to prevent damage caused by the lack of strength in thinned semiconductor substrates. A jig with an outer frame  21 , and a rubber film  22  arranged within the outer frame  21  and having increasing and decreasing body size while deforming its shape by supplying air therein are provided. As the volume of the rubber film  22  increases, the wafer-fixing jig  20  deforms the rubber film and allows the tapes  2  and  6  arranged between the wafer  1  and the rubber film  22 A to be pushed toward the wafer  1  gradually from the center outward. The attachment step, the back grind step, the tape reapplication step, the pick up step and the die bonding step are conducted using such wafer-fixing jig.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. Ser. No.10/708,067, filed on Feb. 6, 2004 (which is a divisional application ofU.S. Ser. No. 10/101,169, filed on Mar. 20, 2002), the entire contentsof which are incorporated herein by reference.

DESCRIPTION BACKGROUND OF THE INVENTION

This application claims the benefit of a Japanese Patent Application No.2001-322811 filed Oct. 19, 2001 in the Japanese Patent Office, thedisclosure of which is hereby incorporated by reference.

1. Field of the Invention

The present invention generally relates to jigs for semiconductorsubstrates and methods for manufacturing semiconductor devices using thesame, and more particularly to a method of manufacturing a semiconductordevice including a step of back grinding the back surface of thesemiconductor substrate (wafer), a step of dicing for singularizing intosemiconductor elements, and a step of bonding including picking up suchsingularized semiconductor elements and mounting them to the mountingdevice; as well as to a jig for semiconductor devices used for such amethod.

Recently, with the necessity for semiconductor packages to be light,thin, short and small, the related wafers are also becoming thinner.

In each step such as in the back grind step, when the thickness of thewafer is less than 100 .mu.m, the wafer transportation and thesemiconductor manufacturing process are technically very difficult usingconventional methods. For this reason, a method of securely transportingand performing the process of semiconductor manufacturing with thinnerwafers is desired.

2. Description of the Related Art

Conventionally, in manufacturing steps consisting of back grinding thesemiconductor substrate (hereinafter also referred to as the wafer),singularizing the wafer into semiconductor elements by dicing, andbonding the singularized semiconductor elements on, for example, themounting substrate, the transportation and the predetermined processesare carried out with the wafer attached to a tape. Each manufacturingstep is described with reference to FIG. 1.

First, as shown in FIG. 1A, a circuit-forming surface is attached to aprotection tape 2 (attachment step). Subsequently, as shown in FIG. 1B,the wafer 1 is installed to a chuck table 4 and the back surface of thewafer 1 is back grounded by a rotating grind whetstone 3 (back grindstep). As a result, the wafer 1 is thinned.

Secondly, a die attach film (not shown) is attached to the back surfaceof the thinned wafer 1 (die attach mount step).

Subsequently, as shown in FIG. 1C, as the protection tape 2 attached tothe wafer 1 is peeled, the back surface of the wafer 1 is attached to adicing tape 6 (tape reapplication step). The dicing tape 6 is previouslyarranged in a frame 5 having a shape of a frame.

Next, as shown in FIG. 1D, the wafer 1 is cut along the predetermineddicing line using a dicing saw 7, and the wafer is singularized intosemiconductor elements 10 (singularization step).

The singularized semiconductor elements 10 are pressed on their backsurfaces through the dicing tape 6 using a push up pin 11 and as aresult, the semiconductor elements 10 are peeled from the dicing tape 6,as shown in FIG. 1E. A collet 8 is located opposite the push up pin 11on the upper side, and the peeled semiconductor elements 10 are adsorbedto and held by the collet 8 (pick up step).

The semiconductor elements 10 held by the collet 8 are transferred tothe mounting substrate 9 as the collet 8 moves, and are bonded to thepredetermined position on the mounting substrate 9 by the die attachfilm (bonding step). Through these steps, the semiconductor elements 10formed on the wafer 1 are thinned and singularized, and then mounted onthe mounting substrate 9.

The wafer 1 made extremely thin by the back grind step warps, which wasnot a problem with a conventional thickness. The thinning of the wafer 1is not only the direct cause of reduction in the absolute strength ofthe wafer. When the wafer 1 warps, the performance of each manufacturingstep after the back grind step is degraded, and along withtransportation of the wafer becomes a factor of breakage failure.

This is significant particularly in the tape reapplication step. Inother words, during the tape application, bubbles are likely to enterbetween the wafer 1 and the dicing tape 6 if the wafer 1 is thin.

When bubbles enter, the wafer 1 and the dicing tape 6 do not adhere atthe locations where bubbles exist, and thus the adhesive strengthbetween the wafer 1 and the dicing tape 6 decreases. Furthermore, whenheat is applied, the bubbles expand and the wafer 1 and the dicing tape6 are further separated from each other. Therefore, when bubbles enter,there is a possibility that an appropriate process may not besuccessfully performed in the steps subsequently conducted (for example,the singularization step), and the yield of the semiconductormanufacturing process is lowered, and in the worst case, the wafer 1 maybreak due to the expansion of bubbles.

On the other hand, in considering peeling the protection tape, the wafer1 may break when the protection tape 2 is being peeled, or the wafer 1may be peeled from the periphery at the start of peeling, and thenbreak.

SUMMARY OF THE INVENTION

In view of the above problems, the general object of the presentinvention is to provide a jig for holding the semiconductor substrate sothat there is little effect from thinned semiconductor substrates, andfor suppressing the occurrence of damage caused by lack of semiconductorsubstrate strength; and to provide a method of manufacturing asemiconductor device using the jig.

The above object of the present invention is achieved by the followingmeasures of the present invention.

The object of the present invention is achieved by a method ofmanufacturing a semiconductor device using a semiconductor substratejig, wherein a method comprises the steps of fixing a semiconductorsubstrate flatly to a semiconductor substrate jig so as to prevent warpsfrom occurring in the semiconductor substrate; and dicing thesemiconductor substrate into a plurality of semiconductor elements whilefixed to the semiconductor substrate jig.

According to this invention, since the semiconductor substrate is fixedto the semiconductor substrate jig without warps, the dicing step of thesemiconductor substrate can be carried out smoothly.

The object of the present invention is further achieved by a method ofmanufacturing a semiconductor device using a semiconductor substrate jigcomprising the steps of fixing a semiconductor substrate flatly to thesemiconductor substrate jig so as to prevent warps from occurring in thesemiconductor substrate; and back grinding the semiconductor substratewhile attached to the semiconductor substrate jig.

According to this invention, since the semiconductor substrate is fixedto the semiconductor substrate jig without warps, the back grind step ofthe semiconductor substrate can be carried out smoothly.

The object of the present invention is achieved by a semiconductorsubstrate jig used for arranging a film on a semiconductor substrate,wherein the jig has a frame, an expandable member arranged within theframe and increasing or decreasing volume while deforming a shape bybeing supplied with fluid therein; and the shape is deformed so that thefilm arranged between the semiconductor substrate and the expandablemember presses against the semiconductor substrate as contacting portionof the expandable member to the film is enlarged outwardly from thecenter of the film as the volume increases.

According to the present invention, when the volume of the expandablemember increases, the film arranged between the semiconductor substrateand the expandable member deforms so as to be gradually pushed towardthe semiconductor substrate from the center outward, and thus the air(bubbles) between the semiconductor substrate and the film is pushedoutward from by the center outward as the expandable member deforms.

Therefore, the bubbles are prevented from remaining between thesemiconductor substrate and the film, and the subsequent manufacturingsteps are conducted smoothly and thus the breakage failure of thesemiconductor substrate caused by the bubbles is prevented.

The above object of the present invention is also achieved by a methodof manufacturing a semiconductor device using a semiconductor substratejig described above, wherein the method has steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   back grinding a back surface of the semiconductor substrate        while attached to the semiconductor substrate jig;    -   reapplying and fixing the semiconductor substrate to a second        semiconductor substrate jig so as to expose the circuit-forming        surface;    -   singularizing the semiconductor substrate fixed on the second        semiconductor substrate jig into a plurality of semiconductor        elements by dicing; and    -   picking up each of the singularized semiconductor elements from        the second semiconductor substrate jig.

According to the above method of the present invention, since thesemiconductor substrate jig is used, the bubbles are prevented fromremaining between the semiconductor substrate and the first adhesivetape, and the semiconductor substrate is securely held to thesemiconductor substrate jig in the back grind step. Thus, the back grindstep is conducted smoothly.

The object of the present invention is further achieved by a method ofmanufacturing a semiconductor device using a semiconductor substratejig, wherein the method comprises the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   back grinding a back surface of the semiconductor substrate        while attached to the semiconductor substrate jig;    -   singularizing the back grounded semiconductor substrate fixed on        the semiconductor substrate jig into a plurality of        semiconductor elements by dicing;    -   reapplying and fixing all of the semiconductor elements on a        second semiconductor substrate jig so as to collectively expose        the circuit-forming surface; and    -   picking up each of the singularized semiconductor substrates        from the second semiconductor substrate jig.

As described above, after the back grind step is completed, the tapereapplication step may be conducted before or after performing thesingularization step.

The object of the present invention is furthermore achieved by a methodof manufacturing a semiconductor device using a semiconductor substratejig described above, wherein the method comprises the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   back grinding a back surface of the semiconductor substrate        while attached to the semiconductor substrate jig;    -   singularizing the back grounded semiconductor substrate fixed to        a second semiconductor substrate jig into a plurality of        semiconductor elements by dicing; and    -   picking up each of the singularized semiconductor elements from        the second semiconductor substrate jig and turning the picked up        semiconductor elements upside down.

According to the above method of the present invention, since the tapereapplication step does not exist, the damage to the semiconductorsubstrate is prevented and there is no possibility of bubbles enteringbetween the semiconductor substrate and the adhesive tape at the time ofreapplication.

The object of the present invention is also achieved by a method ofmanufacturing a semiconductor device using a semiconductor substrate jigdescribed above, wherein the method comprises the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   singularizing the semiconductor substrate fixed on the        semiconductor substrate jig into a plurality of semiconductor        elements by dicing;    -   back grinding collectively back surfaces of plural semiconductor        element attached to the semiconductor substrate jig;    -   reapplying and fixing the semiconductor elements collectively to        a second semiconductor substrate jig so as to expose the        circuit-forming surface; and    -   picking up each of the semiconductor elements from the second        semiconductor substrate jig.

The object of the present invention is achieved by a method ofmanufacturing a semiconductor device using a semiconductor substrate jigdescribed above, wherein the method comprises the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   singularizing the semiconductor substrate fixed on the        semiconductor substrate jig into a plurality of semiconductor        elements by dicing;    -   back grinding back surfaces of plural singularized semiconductor        elements attached to the semiconductor substrate jig; and    -   picking up each of the singularized semiconductor elements from        the second semiconductor substrate jig and turning the picked up        semiconductor elements upside down.

When the above method is used, by conducting the back grind step afterthe singularization step is completed, the strength of the semiconductorelement is increased. Further, because the reapplication step isexcluded, the damage to the semiconductor element and the entering ofbubbles between the semiconductor element and the adhesive tape areprevented.

The object of the present invention is achieved by a semiconductorsubstrate jig used for arranging a film on a semiconductor substrate,wherein the jig comprises:

-   -   a frame with a bottom;    -   a set of plural annular members arranged concentrically within        the frame and constructed so as to be individually movable in a        direction perpendicular to the semiconductor substrate, the        height of the annular members in the direction perpendicular to        the semiconductor substrate gradually increasing from an outer        circumference toward an inner circumference;    -   a biasing member for biasing each of the annular members toward        the bottom of the frame; and    -   an operating member contacting the annular members by operating        movement in the frame and provided for biasing in a direction        separating the annular members from the bottom of the frame        against the bias force of the biasing member; wherein    -   each of the annular members moves so as to gradually presses the        film arranged between the semiconductor substrate and the set of        annular member toward the semiconductor substrate from center        outward with the operation of the operating member.

According to the above method of the present invention, with theoperation of the operating member, each annular member is independentlymoved and gradually presses the film toward the semiconductor substratefrom the center outward. Thus, the air (bubbles) between thesemiconductor substrate and the film is pushed from the center outwardwith the movement of the annular member.

Therefore, the bubbles are prevented from existing between thesemiconductor substrate and the film, and the subsequent manufacturingsteps are smoothly conducted and the damage to the semiconductorsubstrate caused by the entering of the bubbles is prevented.

The object of the present invention is achieved by a method ofmanufacturing a semiconductor device using a semiconductor substratejig, wherein the method comprises the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to the semiconductor substrate jig using a first        adhesive tape as the film;    -   back grinding a back surface of the semiconductor substrate        while attached to the semiconductor substrate jig;    -   die attach mounting for arranging die attach material to the        back surface of the semiconductor substrate;    -   reapplying and fixing the semiconductor substrate on a second        semiconductor substrate jig and exposing the circuit-forming        surface;    -   singularizing the semiconductor substrate fixed on the second        semiconductor substrate jig into a plurality of semiconductor        elements by dicing; and    -   picking up each of the singularized semiconductor elements from        the second semiconductor substrate jig.

According to the above method of the present invention, the entering ofbubbles between the semiconductor substrate and the first adhesive tapeis prevented, and the semiconductor substrate is securely held by thesemiconductor substrate jig in the back grind step. Thus, the back grindstep is conducted smoothly.

The object of the present invention is achieved by semiconductorsubstrate jig used in arranging a film to a semiconductor substrate,wherein the jig comprises:

-   -   a frame;    -   a porous member arranged within the frame so as to be opposite        the film; and    -   a vacuum hole formed in the frame and provided for applying        negative pressure to the porous member.

With the above semiconductor substrate jig, it is possible to preventbubbles from entering between the film and the semiconductor substratebecause the film is adsorbed to the semiconductor substrate jig throughthe negative pressure applied to the porous member and thus the film isplaned.

The object of the present invention is achieved by a method ofmanufacturing a semiconductor substrate comprising the steps of:

-   -   attaching a circuit-forming surface of the semiconductor        substrate to a semiconductor substrate jig that transmits light        using a double-sided tape applied with an adhesive having        ultraviolet curing properties on both sides;    -   back grinding a back surface of the semiconductor substrate        attached to the semiconductor substrate jig;    -   irradiating ultraviolet rays to adhesives having the ultraviolet        curing properties through the semiconductor substrate;    -   reapplying for arranging die attach film to the back surface of        the semiconductor substrate, reapplying and fixing the        semiconductor substrate to a second semiconductor substrate jig,        and then exposing the circuit-forming surface;    -   singularizing the semiconductor substrate fixed on the second        semiconductor substrate jig into a plurality of semiconductor        elements by dicing; and    -   picking up each of the singularized semiconductor elements from        the second semiconductor substrate jig.

According to the above method of the present invention, as the materialthat transmits light is selected to be used as the semiconductorsubstrate jig, ultraviolet rays can be irradiated to the adhesives withthe properties of ultraviolet curing through the semiconductor substratejig in the tape reapplication step even if the back grind step isconducted with the semiconductor substrate adhering to the semiconductorsubstrate jig.

The object of the present invention is achieved by a semiconductorsubstrate jig comprising:

-   -   a first jig having a first suction mechanism sucking the        semiconductor substrate; and    -   a second jig having a second suction mechanism sucking the        semiconductor substrate;    -   the first and second jigs being removably constructed and        independently sucking the semiconductor substrate.

According to the above jig of the present invention, because the firstand the second suction mechanisms can independently suck thesemiconductor substrate, the semiconductor substrate can be mountedindependently to the first or the second jig. Thus, when the first jigand the second jig are combined, the semiconductor substrate can besuctioned using the first Suction mechanism and the second suctionmechanism.

Therefore, in case suction is switched from the first suction mechanismto the second suction mechanism, the suction of the second suctionmechanism starts while the first suctioning mechanism is stillsuctioning, and then the suction by the first suction mechanism isreleased, thus the semiconductor substrate is constantly suctioned. Thesemiconductor substrate is prevented from warping because thesemiconductor substrate is held either by the first or the second jigeven if the semiconductor substrate is thinned.

BRIEF DESCRIPTION OF THE DRAWINGS

The description of the preferred embodiments of the present inventionwill now be explained with reference to the figures in which:

FIGS. 1A-1E are flow diagrams for explaining conventional method ofmanufacturing a semiconductor device;

FIG. 2A is a top view showing a semiconductor substrate jig according toa first embodiment of the present invention;

FIG. 2B is a cross sectional view showing the semiconductor substratejig according to a first embodiment of the present invention;

FIGS. 3A-3G are flow diagrams for explaining the method of manufacturinga semiconductor device according to the first embodiment of the presentinvention;

FIGS. 4A-4D are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a first embodiment ofthe present invention;

FIGS. 5A-5C are flow diagrams explaining in detail steps of attaching awafer to the jig;

FIGS. 6A-6G are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a second embodiment ofthe present invention;

FIGS. 7A-7I are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a third embodiment ofthe present invention;

FIGS. 8A-8I are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a fourth embodiment ofthe present invention;

FIG. 9A is a top view showing a semiconductor substrate jig according tothe second embodiment of the present invention;

FIG. 9B is a cross sectional view showing the semiconductor substratejig according to the second embodiment of the present invention;

FIG. 9C is a right side view showing the semiconductor substrate jigaccording to the second embodiment of the present invention;

FIG. 10A-10E are diagrams showing the operations of the semiconductorsubstrate jig according to the second embodiment of the presentinvention;

FIG. 11A-11H are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a fifth embodiment ofthe present invention;

FIGS. 12A-12H are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a sixth embodiment ofthe present invention;

FIG. 13A is a top view showing semiconductor substrate jig according tothe third embodiment of the present invention;

FIG. 13B is a cross sectional view showing the semiconductor substratejig according to the third embodiment of the present invention;

FIG. 14A is a top view showing a semiconductor substrate jig accordingto the fourth embodiment of the present invention;

FIG. 14B is a cross sectional view showing the semiconductor substratejig according to the fourth embodiment of the present invention;

FIGS. 15A-15H are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to a seventh embodimentof the present invention;

FIG. 16A is a top view showing a semiconductor substrate jig accordingto the fifth embodiment of the present invention;

FIG. 16B is a cross sectional view showing the semiconductor substratejig according to the fifth embodiment of the present invention;

FIG. 16C is a cross sectional view showing the state in which the lowerjig and the upper jig are separated according to the fifth embodiment ofthe semiconductor substrate jig of the present invention; and

FIG. 17A-17J are flow diagrams explaining in detail the method ofmanufacturing a semiconductor device according to the eighth embodimentof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 shows a wafer-fixing jig 20 according to a first embodiment ofthe present invention. FIG. 2A is a top view of the wafer-fixing jig 20,and FIG. 2B is a cross sectional view of the wafer-fixing jig 20.Components having the same structure as those previously described withreference to FIG. 1 are explained with the same reference numbers.

The wafer-fixing jig 20 generally includes for example, a rubber film22, a set table 23, and a porous plate 24. The outer frame 21 is acylinder shaped member made from metal (ceramic and resin are alsopossible), and floor 25 is placed in the center (refer to FIG. 2B). Thesize of the outer frame 21 (diameter when seen from the top) is set tobe slightly larger than the external shape of the wafer 1. The rubberfilm 22 is arranged on the upper part of the floor formed in thewafer-fixing jig 20.

The rubber film 22 is made elastic by injecting fluids (in thisembodiment, air, but, other gases or fluids are also possible) inside.The rubber film 22 has a thickness of between 0.2 mm and 0.8 mm, and theuse of materials such as butyl rubber, fluorinated rubber, andethylene-propylene rubber is desirable considering the strength and theenvironment in which it is used.

Air is introduced from and exhausted to the inside of the rubber film 22through a first air joint 26 provided in the floor 25. The bottom partof the rubber film 22 is attached in an air tight manner to the floor25. Furthermore, a disk shaped set table 23 with the same diameter asthat of the wafer 1 is arranged inside the rubber film 22.

On the under surface of the set table 23, four guide shafts 27 and asecond air joint 28 are provided. Each guide shaft 27 and the second airjoint 28 are movably journaled to the floor 25.

The guide shafts 27 and the second air joint 28 are constructed so as topass through the floor 25, but cause no air leakage where the guideshafts and the air joint pass through thanks to sealing members arrangedbetween the floor 25 and the guide shafts 27, as well as between thefloor 25 and the air joint 28.

A porous plate 24 is arranged on the top surface of the set table 23.The porous plate 24 is connected to the second air joint 28 and enablessuction or air introduction.

An air supply/exhaust device (not shown) is connected to the first airjoint 26 and the second air joint 28. An elevating mechanism (not shown)for elevating the set table 23 is connected to the guide shafts 27.

Next, a method of manufacturing a semiconductor device using theconstructed wafer-fixing jig 20 is explained.

The characteristics of the present invention can be found, for example,in the attachment step, in the back grind step, in the tapereapplication step, in the singularization step, and in the pick upstep; and other manufacturing steps that refer to methods well known inthe art. Thus, the following descriptions only concern each of the abovesteps, and descriptions of other well-known manufacturing steps areomitted.

FIG. 3A through FIG. 3G show a method of manufacturing the semiconductordevice according to the first embodiment. First, a protection tape 2 isattached to the wafer 1 by means of the wafer-fixing jig 20A, as shownin FIG. 3A. The protection tape 2 is also attached to the rubber film22A of the wafer-fixing jig 20A. Although the wafer-fixing jig 20A isthe same as the wafer-fixing jig 20 shown previously in FIG. 2, becausetwo jigs are used in this embodiment, the letters “A” and “B” are usedto represent each jig and to distinguish one from the other.

The method of attaching the protection tape 2 to the wafer 1 by means ofthe wafer-fixing jig 20 is explained with reference to FIG. 4A throughFIG. 4D.

FIG. 4A shows a state before the protection tape 2 is attached to thewafer 1 (hereinafter referred to as an pre-attachment state). In thepre-attachment state, the wafer 1 is adsorbed and held by the wafer hand29 with the circuit-forming surface side facing down, as shown in thefigure. The previously explained wafer-fixing jig 20A is placed belowthe wafer 1. The protection tape 2 is provided between the wafer 1 andthe wafer-fixing jig 20A, by a device not particularly shown.

The protection tape 2 is a so-called double-sided tape with adhesivematerials applied on both sides. The adhesives have a property in whichheating decreases their adhesive strength. Therefore, if the heatingtemperature of the protection tape 2 is in a relationship expressed as(under surface temperature)>(top surface temperature), the adhesivestrength of the under surface will first decrease and then the adhesivestrength of the top surface will decrease as the temperature rises.

In the pre-attachment state, air is pressured to the inside of therubber film 22A from the first air joint 26A provided in the floor 25,and the rubber film 22A expands and deforms Outwardly from the centerdue to its property (refer to FIG. 4B). The deformation of rubber film22A causes the protection tape 2 to be pushed toward the wafer 1.

As mentioned above, the adhesives are applied to both sides of theprotection tape 2. For this reason, the protection tape 2 will beattached to the wafer 1 and at the same time to the rubber film 22A ofthe wafer-fixing jig 20A. This attachment is carried out ideally fromthe center toward the periphery so that there will be little chance ofbubbles entering between the protection tape 2 and the wafer 1.

When the wafer 1 is completely sandwiched from the top and the bottombetween the wafer hand 29 and the rubber film 22A (the state shown inFIG. 4C), the elevation mechanism is activated causing the set table 23Ato rise, and be locked with the wafer 1 in a contacted manner throughthe rubber film 22A and the protection tape 2.

Next, an air supply/exhaust device is activated, performing the suctionprocess through the second air joint 28A. Thus, a negative pressure isproduced in the porous plate 24A and the rubber film 22A is adsorbed andis fixed to the porous plate 24A.

The attachment of the protection tape 2 to the wafer-fixing jig 20A iscompleted through these operations, and the wafer hand 29 is thenremoved from the wafer 1. Finally, the protection tape 2 is cut tosubstantially the same diameter as that of the wafer 1. Attaching thewafer 1 to the wafer-fixing jig 20A through the protection tape 2 can beeasily carried out so that bubbles will not enter between them even ifthe attachment is not conducted under the vacuum environment.

Referring back to FIG. 3, the steps after the step of attaching thewafer to the jig are explained.

After the attachment step mentioned above is completed, the next step inwhich the wafer 1 is transported along with the wafer-fixing jig 20A tothe back grind device (not shown) for thinning the back surface of thewafer is conducted. In the back grind device, the back surface of thewafer 1 is subjected to a grinding process. This process may be amechanical process, a chemical process, or any other process.

The set table 23A is locked at its top position and the rubber film 22Ais adsorbed by the porous plate 24A due to the negative pressure. Thus,because the rubber film 22 is fixed to the porous plate 24A, the wafer 1attached to the rubber film 22 through the protection tape 2 is alsosecurely fixed to the wafer-fixing jig 20A.

However, it is sometimes better to have a mechanism where a certaindegree of vibration during the back grinding process is absorbed,depending on the thickness of the wafer 1 subjected to the back grindingprocess. The air pressure of about 0.01 Mpa to 0.05 Mpa is then providedto the inside of the rubber film 22A, lowering the set table 23Aslightly. The rubber film 22A acts as an air suspension device. Sincethe wafer 1 will then be fabricated oil the jig with an air suspensionfunction, the polishing quality will be more stable.

When the back grind step is completed, the wafer 1 is thinned andwarped, but this warping is not significant since the wafer 1 is fixedto the wafer-fixing jig 20A by the protection tape 2. Furthermore,although the strength of the wafer 1 is reduced because it is thinner,the wafer 1 does not break since the wafer-fixing jig 20A acts asreinforcement to the wafer 1.

After the above back grind step is completed, the next step, which isthe tape reapplication step of reapplying the tape for singularization,is conducted. The reapplication step is explained in detail withreference to FIG. 5.

In this embodiment, the wafer-fixing jig 20B is used in addition to thewafer-fixing jig 20A for conducting the reapplication step. In otherwords, in this embodiment, two wafer-fixing jigs 20A, 20B (both havingthe same construction) are used to conduct the tape reapplication step.

As shown in FIG. 5A, the wafer-fixing jig 20A with the wafer 1 attached,having completed the back grind step, is turned upside down and thenplaced on top of the wafer-fixing jig 20B. A heating process is thenconducted on the protection tape 2 in a manner not shown in the figure,and the adhesive strength of the surface contacting the wafer 1decreases due to the properties of the protection tape 2 used. Here, theadhesive strength of the surface on the side contacting the wafer-fixingjig 20A, which requires a higher heating temperature, is not yetdecreased (the adhesive strength still remains the same).

On the other hand, the wafer-fixing jig 20B is placed below thewafer-fixing jig 20A provided as above. Furthermore, a dicing tape 6 tobe applied to the back surface side of the wafer 1 is provided betweenthe wafer-fixing jig 20A and the wafer-fixing jig 20B.

An adhesive, with the property in which heating decreases adhesivestrength, is applied on both sides of the dicing tape 6. The heatingtemperature for decreasing the adhesive strength of the adhesive is setso that the heating temperature of the under surface (surface facing therubber film 22B) is higher than the heating temperature of the topsurface (surface facing the wafer 1).

When the wafer-fixing jig 20A with the wafer, and the wafer-fixing jig20B are placed in a top and bottom position so as to be opposite oneanother and attached by the dicing tape 6, the wafer-fixing jig 20B inthe lower position operates similar to that explained with reference toFIG. 4A through FIG. 4D.

Generally, introducing air from the first air joint causes the volume ofthe rubber film 22B to increase, and the dicing tape 6 is then attachedto the back surface of the wafer 1 from the center outward. The dicingtape 6 is also attached to the rubber film 22B.

Thereafter, the set table 23B rises and the rubber film 22B is pressedagainst the wafer 1 through the dicing tape 6. Next, a negative pressureis applied to the second air joint 28B and the rubber film 22B is fixedto the porous plate 24A. After the above processes are completed, thewafer 1 is held between the wafer-fixing jig 20A and the wafer-fixingjig 20B, as shown in FIG. 5B.

Next, the set table 23A provided in the wafer-fixing jig 20A in an upperposition is moved (upward direction in the figure) so as to be separatedfrom the wafer 1, and at the same time the air within the rubber film22A is exhausted through the first air joint 26A. As a result, thevolume of the rubber film 22A is smaller (contracts) due to its ownelastic restoring force.

With the contraction of rubber film 22A, the protection tape 2 is peeledfrom the boundary face of the wafer 1 having a decreased adhesivestrength caused by the heating process, as described above. When peelingthe protection tape 2 from the wafer 1, the operation performed will bethe reverse of that performed during attachment due to the properties ofthe rubber film 22A, and thus peeling the protection tape 2 from thewafer 1 is carried out from the periphery towards the center in adirection which is easier to peel (refer to FIG. 5C).

When the protection tape 2 is completely peeled from the wafer 1, thewafer-fixing jig 20A is removed. Afterwards, the dicing tape 6 appliedto the wafer-fixing jig 20B in the lower position is cut tosubstantially the same diameter as that of the wafer 1, and the tapereapplication step is completed. FIG. 3D shows a state in which the tapereapplication step is completed.

Naturally, in order to peel the tape attached to the jig having a rigidbody, the jig must be lifted up with the adhesive strength of the tapebeing zero, or must be slid laterally by performing a special process.However, both are technically very difficult.

Nevertheless, it is possible according to the present invention to carryout the reapplication process easily and securely by using thewafer-fixing jig 20A, 20B of the present embodiment, because thereapplication of the protection tape 2 and the dicing tape 6 areperformed utilizing the deformation of the rubber film 22A, 22B when thevolume increases and decreases. Furthermore, for the reasons mentionedabove, when attaching each tape 2, 6 to the wafer 1 or to the rubberfilm 22A, 22B, it is possible to prevent bubbles from entering.

Referring back to FIG. 3 again, steps following the tape reapplicationstep are explained.

After the tape reapplication step is completed, the wafer 1 istransferred to a dicing device in a state shown in FIG. 3D, in otherwords, in a state in which the wafer 1 is fixed to the wafer-fixing jig20B, and the singularization step for singularizing the wafer 1 intosemiconductor elements 10 is conducted.

The wafer 1 is cut to semiconductor elements 10, but, as shown in FIG.3E, each semiconductor element is still aligned for each of them arefixed onto the wafer-fixing jig 20B through dicing tape 6 even after thesingularization step. In the singularization step, a method of dicing(cutting) the wafer 1 may be mechanical, optical or any other form ofmethod.

After the singularization step is completed, a pick up step for pickingup the semiconductor elements 10 from the wafer-fixing jig 20B (dicingtape 6), and a die bonding step for mounting the semiconductor elements10 to the mounting substrate 9 are conducted, as shown in FIG. 3F andFIG. 3G.

In the pick up step, the dicing tape 6 is subjected to a heating processusing a heating means not shown, and the adhesive strength of thesurface of the dicing tape 6 contacting each semiconductor element isdecreased. Since the surface of the dicing tape 6 contacting the rubberfilm 22B (wafer-fixing jig 20B) is applied with adhesive consisting of amaterial whose adhesive strength decreases at a higher temperature, theadhesive strength on the rubber film 22B side does not decrease at thispoint of heating.

As the adhesive strength between the dicing tape 6 and the semiconductorelements 10 decrease, a collet 8 moves and adsorbs the semiconductorelements through vacuum, and picks up the elements from the dicing tape6. Here, it is ensured that even thinned semiconductor elements 10 witha decreased strength can be securely picked up without damage because ofthe decreased adhesive strength.

The picked up semiconductor elements 10 are transferred to apredetermined position on, for example, the mounting substrate 9 and aredie bonded to the mounting substrate 9. After the pick LIP step and thedie bonding step are conducted for all the semiconductor elements 10attached to the dicing tape 6, the protection tape 2 and the dicing tape6 are peeled from the rubber film 22A, 22B, respectively, by conductinga further heating process at a higher temperature. The wafer-fixing jigs20A, 20B can be recycled.

As explained above, according to this embodiment, the warping of thethinned wafer 1 is not significant and the performance of each step isnot degraded. Furthermore, although the wafer 1 has a decreased strengthdue to being thinned, the wafer-fixing jigs 20A, 20B to which the wafer1 is attached reinforce the wafer and thus no breakage failure willoccur. Furthermore, it is possible to carry out the step of reapplyingthe protection tape 2 with the dicing tape 6 without performing aspecial process by using the wafer-fixing jigs 20A, 20B.

Now, a second embodiment of the present invention according to themethod of manufacturing a semiconductor device is explained.

FIG. 6 is a flow diagram of a method of manufacturing a semiconductordevice according to a second embodiment. In this embodiment as well,each manufacturing step is performed using the wafer-fixing jig 20 shownin FIG. 2.

In FIG. 6, components the same as those shown in FIG. 3 through FIG. 5have the same reference numbers and thus their explanations are omitted.Steps the same as those explained in the first embodiment are omitted toavoid redundancy of the explanation. This holds for each of thesubsequent embodiments explained after the second embodiment.

In this embodiment, the attachment step and the back grind step arecarried out in a similar manner as those explained in the firstembodiment. This embodiment, however, is characterized in that in thetape reapplication step following the back grind step, a conventionallyused frame 5 arranged with a dicing tape 6 is used as the wafer-fixingjig instead of the wafer-fixing jig 20.

In the structure of this embodiment, it is necessary to apply the wafer1 to the dicing tape 6 arranged in the frame 5. Here, there is apossibility that bubbles may enter between the wafer 1 and the dicingtape 6, but although not as completely compared to the first embodiment,the entering of bubbles may be prevented by adopting an attachmentmethod of pressing down with rollers, or an attachment method under avacuum.

According to this embodiment, because there is no need for the dicingtape 6 to be attached to the wafer-fixing jig 20, a step of irradiatingultraviolet rays may be performed before the subsequently performed pickup step, and the flexible ultraviolet curing tape may be used as thedicing tape 6, thus reducing the manufacturing costs.

Next, a third embodiment according to the method of manufacturing thesemiconductor device is explained.

FIG. 7A through FIG. 7I show flow diagrams of a method of manufacturingthe semiconductor device according to a third embodiment. In thisembodiment as well, each manufacturing step is performed using thewafer-fixing jig 20 shown in FIG. 2. In this figure, two manufacturingmethods in which one flows as FIG. 7A.fwdarw.FIG. 7B.fwdarw.FIG.7C.fwdarw.FIG. 7D.fwdarw.FIG. 7E.fwdarw.FIG. 7F.fwdarw.FIG. 7G(manufacturing method 1) and the other flows as FIG. 7A.fwdarw.FIG.7B.fwdarw.FIG. 7C.fwdarw.FIG. 7H.fwdarw.FIG. 7I.fwdarw.FIG. 7G(manufacturing method 2) are shown in the same diagram for convenience.

In this embodiment, the attachment step and the back grind step are thesame as those shown according to the first embodiment (refer to FIG. 3).However, this embodiment is characterized in that in the firstembodiment, the tape reapplication step is conducted after the backgrind step, whereas in this embodiment the singularization step isconducted after the back grind step.

In the manufacturing method 1, the singularization step is notnecessarily performed after the tape reapplication step, and it ispossible to arbitrarily change the order of the singularization step andthe tape reapplication step. Thus, the degree of freedom in designingthe steps is enhanced, and the equipment may be effectively operated. Inthe manufacturing method 1 of this embodiment, two wafer-fixing jigs 20Aand 20B are used to perform the tape reapplication step, but asexplained with reference to FIG. 6, it is also possible to use thedicing tape 6 arranged in the frame 5.

In the manufacturing step 2, it is possible to shift to the pick up stepand the die bonding step immediately after completing thesingularization step. In other words, according to the manufacturingmethod 2, it is possible to eliminate the tape reapplication step. Thus,it is possible to reduce the number of processes compared to theconventional art, and thus reduce the cost and shorten the process time,while facilitating the transportation of the thinned and warped wafer 1,and reinforcing the wafer 1 of decreased strength.

However, it is necessary to perform the die bonding step after thesemiconductor elements 10 picked up by collets 8A, 8B, as shown in FIG.7H, are turned upside down as shown in FIG. 7I, since it is necessaryfor the back surface of the semiconductor elements 10 to be placedopposite the mounting substrate 9 during the die bonding step. The timeneeded for turning upside down is extremely short compared to the timeneeded for the tape reapplication.

Next, a method of manufacturing a semiconductor device according to afourth embodiment of the present invention is explained.

FIG. 8A through FIG. 8I show flow diagrams of the method ofmanufacturing a semiconductor device according to the fourth embodiment.In this figure as well, two manufacturing methods in which one flows asFIG. 8A.fwdarw.FIG. 8B.fwdarw.FIG. 8C.fwdarw.FIG. 8D.fwdarw.FIG.8E.fwdarw.FIG. 8F.fwdarw.FIG. 8G (manufacturing method 1) and the otherflows as FIG. 8A.fwdarw.FIG. 8B.fwdarw.FIG. 8C.fwdarw.FIG.8H.fwdarw.FIG. 8I.fwdarw.FIG. 8G (manufacturing method 2) are shown inthe same diagram for convenience.

This embodiment is characterized in that the singularization step isperformed after the attachment step. Furthermore, this embodiment isconstructed to perform the back grind step and the tape reapplicationstep after the singularization step is completed.

In the manufacturing method 1, the singularization step is notnecessarily performed after the tape reapplication step, and it ispossible to arbitrarily change the order of the back grind step, thesingularization step, and the tape reapplication step. Thus, the degreeof freedom in designing the steps is enhanced and the equipment may beeffectively operated.

Although two wafer-fixing jigs 20A and 20B are used to perform the tapereapplication step in the manufacturing method 1 of this embodiment, itis also possible to use the dicing tape 6 arranged in the frame 5, asexplained with reference to FIG. 6.

In the manufacturing step 2, it is possible to shift to the pick up stepand the die bonding step immediately after completing thesingularization step and the back grind step. In other words, the tapereapplication step may also be eliminated in the manufacturing method 2.

Therefore, the number of processes is reduced compared to theconventional art, and thus the cost is reduced and the process timeshortened, while the transfer of thinned and warped wafer 1 isfacilitated, and the wafer 1 with a decreased strength is reinforced.Furthermore, since the back grind process is carried out after thesemiconductor elements 10 are singularized, the microscopic fragments ofthe edge portion of the semiconductor elements 10 formed during thesingularization step may be removed by the back grind process, and thusthe strength of the semiconductor elements 10 may be enhanced.

However, in this method, it is necessary to perform the die bonding stepafter the semiconductor elements 10 are turned upside down by collets8A, 8B as shown in FIG. 8I. Nevertheless, the time needed for thisturning is extremely short compared to the time needed for the tapereapplication as mentioned before.

Next, a wafer-fixing jig according to a second embodiment of the presentinvention is explained.

FIG. 9A through FIG. 9C show a wafer-fixing jig 30 according to thesecond embodiment. FIG. 9A is a top view of the wafer-fixing jig 30,FIG. 9B is a cross sectional view taken along line A-A of thewafer-fixing jig 30 shown in FIG. 9A, and FIG. 9C is the right side viewof the wafer-fixing jig 30.

The wafer-fixing jig 30 is a jig used for attaching the protection tape2 and the dicing tape 6 to the wafer 1, and for holding the wafer 1applied with tape in a similar way as the above-described wafer-fixingjig 20 (refer to FIG. 2). The wafer-fixing jig 30 is generallyconstructed of an outer frame 31, a set of step rings 32, and a thrustbar 35 (shown in FIG. 10).

The outer frame 31 is a cylindrical member having a bottom, and madefrom metal (ceramic and resin are also possible). The diameter of theouter frame when viewed from the top is set to be somewhat larger thanthe diameter of the wafer 1. Furthermore, a set of step rings 32 (a setof ring shaped member) is placed within the outer frame 31. Furthermore,a pair of grooves 34 is formed on the sidewalls of the outer frame 31,from which grooves 34 the thrust bar 35 (operating member) is insertedas will be described later.

The set of step rings 32 includes plural ring shaped step rings 32 athrough 32 i (only step ring 32 i has a substantially circular shape).These step rings 32 a through 32 i are arranged concentrically withinthe outer frame 31. In other words, the diameters of the step rings aresequentially larger in the order of step ring 32 h.fwdarw.step ring 32g.fwdarw . . . fwdarw.step ring 32 a with the step ring 32 i being thecenter.

Furthermore, the heights in the up and down direction (in the directionperpendicular to the wafer 1, up and down direction in FIG. 9B) of thestep rings 32 a through 32 i are constructed so that the heightgradually gets higher from step ring 32 a in the outer mostcircumference towards step ring 32 i in the inner most circumference.Thus, as shown in FIG. 9B, the height in the up and down direction ofthe step ring 32 a in the outer most circumference has the minimumheight H.sub.A, and the height in the up and down direction of the stepring 32 i in the inner most circumference has the maximum heightH.sub.I.

Furthermore, each step ring 32 a through 32 i is constructed so as to beindividually movable in the up and down direction. However, a tensionspring 33 (bias member) whose one end is connected to the bottom of theouter frame 31 is connected to each step ring 32 a through 32 i. Thus,in the non-operating state (in which thrust bar 35 is not inserted)shown in FIG. 9B, each step ring 32 a through 32 i is biased to thebottom of the outer frame 31 and is in a moved down position. In thisstate, the top surfaces of each step rings 32 a through 32 i are madesubstantially flat.

The thrust bar 35 is a rod shaped member, and is inserted inside theouter frame 31 from groove 34 as mentioned above. Furthermore, the tipof the thrust bar 35 has a tapered portion, as shown in FIG. 10.

Next, the operations of the above constructed wafer-fixing jig 30 areexplained with reference to FIG. 10.

FIG. 10A shows a non-operating state. In the non-operating state, thetop surface of each step rings 32 a through 32 i of the set of steprings 32 is flat as mentioned above.

As the thrust bar 35 is inserted inside the outer frame 31 from thegroove 34 as shown in FIG. 10B, the tapered portion at the tip of thethrust bar engages with the step rings 32 a through step ring 32 i oneby one, biasing and moving up each step ring 32 a through 32 i.

Here, because there is a height difference between each step ring 32 athrough 32 i, when a certain step ring is moved up, all the step ringslocated internal to that step ring will all move Up. Generally, as shownin FIG. 10B, when the thrust bar 35 causes the step ring 32 a in theouter most circumference to move up, the step rings 32 b through 32 iinternal to the step ring 32 a are simultaneously moved up while stillmaintaining a flat state.

Subsequently, as shown in FIG. 10C, when the thrust bar 35 causes thestep ring 32 b located one ring internal to the step ring 32 a to moveup, the step rings 32 c through 32 i internal to the step ring 32 b aresimultaneously moved Up while still maintaining a flat state.Furthermore, as shown in FIG. 10D, when the thrust bar 35 causes thestep ring 32 c located one ring internal to step ring 32 b to move up,the step rings 32 d through 32 i internal to the step ring 32 c aremoved up simultaneously while still maintaining a flat state.

Similar operations are performed repeatedly a number of times as thethrust bar 35 is inserted, and when the bar 35 is completely inserted(hereinafter referred to this condition as the operation completestate), as shown in FIG. 10E, the set of step rings 32 forms a mountainlike shape with the center step ring 32 i being the highest point(height H.sub.I), and the step ring 32 a being the lowest point (heightH.sub.A). When the thrust bar 35 is retracted from the outer frame 31,each step ring 32 a through 32 i operate in a reverse manner as theoperations stated above. The material of each step ring 32 a through 32i consists of metal, ceramic, and resin, and the appropriate differencein height between each step ring 32 a through 32 i is about 0.5 to 2 mm,and the width is about 2 to 10 mm.

Next, a method of manufacturing a semiconductor device using the aboveconstructed wafer-fixing jig 30 is explained.

The characteristics of this embodiment can be found in the attachmentstep, the back grind step, the tape reapplication step, thesingularization step, and the pick up step, and other manufacturingsteps use the well-known method. For this reason, the followingexplanations only concern each of the above-explained steps andexplanations regarding other well-known manufacturing steps are omitted.

FIG. 11A thorough FIG. 11H show the method of manufacturing asemiconductor device according to a fifth embodiment. First, as shown inFIG. 11A, protection tape 2 is attached to the wafer 1 using thewafer-fixing jig 30A (step for attaching the wafer to the jig). Here,the protection tape 2 is also attached to the top surface of the set ofstep rings 32 of the wafer-fixing jig 30A. The wafer-fixing jig 30A isthe same as the wafer-fixing jig 30 shown in FIG. 9, but because twojigs are used as will be stated later in this embodiment, the letters“A” and “B” are used to represent each construction and to distinguishone from the other.

To attach the protection tape 2 to the wafer 1, the wafer-fixing jig 30Amust be in the operation complete state beforehand. The protection tape2 is provided between the wafer 1 and the wafer-fixing jig 30A, and thewafer-fixing jig 30A is partially in contact with the wafer 1 throughthe protection tape 2.

In the state shown in FIG. 11A, only the center step ring 32 i of theset of step rings 32 partially contacts the protection tape 2 becausethe wafer-fixing jig 30A is in an operation complete state as mentionedabove. The adhesives, with the property that heating decreases theiradhesive strength, are applied to both sides of the protection tape 2.In this embodiment, the temperature characteristics of the adhesivesapplied to the top and the under surfaces of the protection tape 2 ismade the same.

Next, the thrust bar 35 is pulled in the direction shown by the arrowsin FIG. 11A. Each of the step rings 32 a through 32 i of thewafer-fixing jig 30A gradually lowers from the center outward.

The wafer hand 29 holds the wafer 1, but synchronizes with the loweringaction of each step ring 32 a through 32 i, and is constructed to dropan amount corresponding to the amount of the lowering stroke. Thus, theset of step rings 32 and the wafer 1 are always in a contacted stateeven while each of the step ring 32 a through 32 i is moving. Then, thethrust bar 35 is pulled further out, and when the bar is completelypulled out of the outer frame 31 (i.e. non-operating state), the topsurface of the set of step rings 32 is flat.

The series of actions of the set of step rings 32 (step ring 32 athrough 32 i) are actions in which step rings 32 a through 32 igradually rise relatively from the center outward when seen from thewafer 1. With these actions of step ring 32 a through 32 i, theprotection tape 2 is attached to the wafer 1 and to the top surface ofthe set of step rings 32.

Here, the protection tape 2 is attached a step at a time from the centerof the wafer 1 outward because the step rings 32 a through 32 isequentially rise relatively from the center outward. Thus, even ifbubbles exist between the wafer 1 and the protection tape 2, the bubblesare pushed outward due the above action of the step rings 32 a through32 i, and eventually no bubbles will exist between the wafer 1 and theprotection tape 2. Thus even in the attachment process in thisembodiment, the attachment is carried out ideally from the centeroutward so that there is little chance of bubbles entering between theprotection tape 2 and the wafer 1.

When the protection tape 2 is attached to the wafer 1 and the topsurfaces of the set of step rings 32, the wafer hand 29 is removed fromthe wafer 1, and the protection tape 2 is cut to substantially the samediameter as that of the wafer 1. Consequently, the attachment step iscompleted. As stated above, in this embodiment as well, the attachmentbetween the wafer 1 and the protection tape 2 can be readily carried outso that no bubbles will enter even if the attachment is not conducted ina vacuum environment, by using the wafer-fixing jig 30A.

After the attachment step is completed, as shown in FIG. 11B, the backgrind step is conducted. The back grind step is conducted to the wafer 1fixed to the wafer-fixing jig 30A. The general method of the grindingprocess may be a mechanical process, a chemical process or any otherprocesses.

When the back grind step is completed, the wafer 1 is thinned andwarped, but because wafer 1 is fixed to the wafer-fixing jig 30A by theprotection tape 2, the warping is not significant. The strength of thewafer 1 is decreased due to being thinned, but since wafer-fixing jig30A serves to reinforce the wafer 1, wafer 1 will not break.

After the back grind step is completed, the die attach mount step shownin FIG. 11C is conducted. In the die attach mount step, a die attachfilm 37 is applied to the back surface of the wafer 1.

The die attach film is applied by means of a method of pushing down withfor example, rollers not shown in the figure. The die attach film is, aswill be stated later, a material for securing the semiconductor elements10 and the mounting substrate 9 when mounting the semiconductor elements10 to the mounting substrate 9.

When the die attach film 37 is applied to the back surface of the wafer1, and in case it is necessary to change the temperature depending onthe type of the die attach film 37, a heating mechanism is provided inthe wafer-fixing jig 30A with which the die attach film 37 is heated.

After the die mount step is completed, the tape reapplication step isconducted. In this embodiment, the wafer-fixing jig 30B is used inaddition to the wafer-fixing jig 30A to carry out the tape reapplicationstep. In other words, in this embodiment, the tape reapplication processis conducted using two wafer-fixing jigs 30A and 30B (both having thesame construction).

As shown in FIG. 11D, the wafer-fixing jig 30A, with the wafer 1 havingcompleted the back grind step attached, is turned upside down and placedon top of the wafer-fixing jig 30B. Heating process is conducted to theprotection tape 2 in a manner not shown in the figure, and the adhesivestrength of each of the adhesives applied to both sides of theprotection tape 2 decreases.

In the wafer-fixing jig 30B in the lower position, a double-sided tape36 is applied to the top surfaces of the set of step rings 32B. Anadhesive whose adhesive strength is decreased by heat application isapplied to both sides of the double-sided tape 36. The temperaturecharacteristics of the adhesive are set so that the temperature fordecreasing the adhesive strength of the adhesive applied to the topsurface of the double-sided tape 36 (the surface opposite the wafer 1)is higher than the temperature for decreasing the adhesive strength ofthe adhesive applied to the under surface of the double-sided tape 36(surface opposite the wafer-fixing jig 30B).

The wafer 1 fixed on the wafer-fixing jig 30A is attached to thedouble-sided tape 36. Here, each step ring 32 a through 32 i of thewafer-fixing jig 30B perform a similar action as those stated above, andthus the attachment of the double-sided tape 36 and the wafer 1 proceedsfrom the center outward. It is possible to prevent bubbles from enteringbetween the double-sided tape 36 and the wafer 1 (generally, die attachfilm 37). After a series of processes are completed, the wafer 1 will besandwiched between the wafer-fixing jig 30A and the wafer-fixing jig30B.

Next, the wafer-fixing jig 30A in the upper position is operated and thethrust bar 35 is inserted to the inside of the outer film 31. With thisaction, the step rings 32 a through 32 i are gradually lowered from theouter circumference toward the center (lowering or dropping refers tothe movement in a direction in which the step rings 32 a through 32 iseparate from the wafer 1).

With the movement of each step ring 32 a through 32 i, the entirewafer-fixing jig 30A is raised (upward movement in FIG. 11).

Due to this action, the peeling at the boundary face between thewafer-fixing jig 30A and the protection tape 2 proceeds. This is areverse action to the attachment action and peeling starts from theouter circumference toward the center in a direction easier to proceed.Eventually, the protection tape 2 is completely peeled from thewafer-fixing jig 30A.

As shown in FIG. 11E, the remainder of the protection tape 2 is peeledfrom the wafer 1. The peeling process of the protection 2 is easilyperformed because heating decreases the adhesive strength of theadhesives applied to the protection tape 2, and because the tape body ofthe protection tapes 2 is soft. After peeling, the double-sided tape 36is cut to substantially the same diameter as that of the wafer 1 andfinally the series of processes for the tape reapplication step iscompleted.

After the reapplication step is completed, the singularization step forsingularizing the wafer 1 into semiconductor elements 10, the pick upstep, and the die bonding step are performed, but besides the fact thatwafer 1 (semiconductor elements 10) is fixed onto the wafer-fixing jig30B, each step is not different from the steps in the manufacturingmethod related to the first embodiment with reference to FIG. 3, andthus their explanations are omitted. By peeling the double-sided tape 36from the set of step rings 32, the wafer-fixing jig 30B can be recycled.

Next, a method of manufacturing the semiconductor device according to asixth embodiment is shown.

FIG. 12A through FIG. 12H show flow diagrams of the method ofmanufacturing the semiconductor device according to the sixthembodiment. In this embodiment as well, each manufacturing step isconducted using the wafer-fixing jig 30 shown in FIG. 9.

In FIG. 12A through FIG. 12H, components same as those shown in FIG. 9through FIG. 11 have the same reference numbers and thus theirexplanations are omitted to avoid redundancy.

In this embodiment, the attachment step and the back grind step arecarried out in a similar way to those explained in the fifth embodiment.This embodiment, however, is characterized in that conventionally usedframe 5 arranged with the dicing tape 6 is used as the wafer-fixing jiginstead of the wafer-fixing jig 30.

In the structure of this embodiment, it is necessary to attach the wafer1 to the dicing tape 6 arranged in the frame 5 in the tape reapplicationstep. Here, there is a possibility that bubbles enter between the wafer1 and the dicing tape 6, but by adopting the method of pressing downwith rollers or conducting the attachment process in a vacuumenvironment, it is possible, although not as completely as shown in thefifth embodiment, to prevent bubbles from entering.

In this embodiment, since there is no need for dicing tape 6 to beattached to the wafer-fixing jig 30, the ultraviolet irradiation stepcan be conducted before the subsequently performed pick up step, and theflexible ultraviolet curing tape used nowadays can be used as the dicingtape 6, thus reducing the manufacturing cost.

In the manufacturing method described in the fifth and the sixthembodiments, the wafer-fixing jig 30 shown in FIG. 9 it used. However,such manufacturing method of the fifth and the sixth embodiments shownin FIG. 11 and FIG. 12, respectively, can be performed withoutnecessarily using the wafer-fixing jig 30.

FIGS. 13A and 13B show a wafer-fixing jig 40 according to the thirdembodiment, in which the wafer-fixing jig 40 is alternatively usable asthe wafer-fixing jig 30.

The wafer-fixing jig 40 includes an outer frame 41 and a porous member42. The outer frame 41 has a somewhat larger diameter than the diameterof the installed wafer 1. A vacuum pore 43 is formed in the center ofthe under part of the outer frame 41, and the vacuum pore 43 isconnected to the vacuum device not shown. The outer frame 41 is composedof metal, ceramic, or resin.

The porous member 42 is arranged within the outer frame 41 and hassubstantially the same diameter as that of the installed wafer 1. Theporous member 42 is connected to the vacuum pore 43 formed in the outerframe 41, and adsorbs the wafer 1 placed on the top thereof.

Through the use of the constructed wafer-fixing jig 40, it is possibleto prevent bubbles from entering between the wafer-fixing jig 40 andeach tape 2, 36 by suctioning while attaching the protection tape 2 andthe double-sided tape 36 to the wafer-fixing jig 40. The tapes 2, 36 maybe easily peeled from the wafer-fixing jig 40 by emitting air.

Next, a method of manufacturing the semiconductor device according to aseventh embodiment of the present invention is shown.

FIG. 15A through FIG. 15H show flow diagrams showing the method ofmanufacturing the semiconductor device according to the seventhembodiment. In this embodiment, a disc 45 shown in FIG. 14 is used. Thedisc 45 is composed of a disc having substantially the same diameter asthat of the wafer 1. The appropriate thickness of the disc is between 1mm to 5 mm and the preferred material is quartz glass that transmitslight.

As shown in FIG. 15A, the wafer 1 is attached to the above constructeddisc 45 using the double-sided tape 46. The double-sided tape 46 may bea flexible ultraviolet curing double-sided adhesive tape. The process ofattaching the wafer 1 to the double-sided tape 46 can use, for example,the method of pushing down with rollers, or the method of applying thedouble-sided tape 46 to the wafer 1 under a vacuum environment. Thedouble-sided tape 46 is attached to the disc 45 after it is attached tothe wafer 1.

After the attachment step is completed, the wafer 1 is subjected to theback grind process while fixed on the disc 45 (back grind step) as shownin FIG. 15B. After the back grind step is completed, the firstultraviolet irradiation step is performed, as shown in FIG. 15C.

In the first irradiation step, the ultraviolet rays irradiate theadhesives applied to the double-sided tape 46 through the disc 45 havingthe property of light transmission. Thus, the adhesives applied to thedouble-sided tape 46 are cured and the adhesive strength is decreased.

After the first ultraviolet irradiation step is completed, the tapereapplication step is conducted. In the tape reapplication step, thewafer 1 fixed to the disc 45 is turned upside down and the back surfaceof the wafer 1 is attached to the dicing tape 6 arranged in the frame 5,as shown in FIG. 15D. Here, the back surface of the wafer 1 may beattached to the dicing tape 6 after the die attach film 37 is mounted.

The ultraviolet curing adhesives may be applied to the dicing tape 6beforehand through which the wafer 1 is attached to the dicing tape 6.Through the attachment method by pressing down with rollers and theattachment method of performing under vacuum environment, the wafer 1and the dicing tape 6 are attached to one another without having bubblesbetween them.

After the tape reapplication step is completed, the disc 45 is removedand the singularization step is conducted. The wafer 1 is singularizedinto semiconductor elements 10. Thereafter, a second ultravioletirradiation step is conducted, and ultraviolet rays are irradiated fromthe side of the back surface of the dicing tape 6 (from the undersurface side in the figure). The adhesive strength of the ultravioletcuring type adhesive applied to the dicing tape 6 decreases. The pick upstep and the die bonding step are conducted in the same manner aspreviously described, and the semiconductor elements 10 are mounted tothe mounting substrate 9.

According to this embodiment, since disc 45 having the property of lighttransmission is used as the fixing jig for wafer 1, it is possible toperform ultraviolet irradiation from the under surface of the disc 45 inthe subsequent steps. Thus, the flexible ultraviolet irradiation tapeused conventionally nowadays can still be used and the running costs maybe reduced.

Next, a method of manufacturing the semiconductor device according to aneighth embodiment is shown.

FIG. 16A through FIG. 16C show a wafer-fixing jig 50 used in the methodof manufacturing the semiconductor device according to the eighthembodiment, and FIG. 17A through FIG. 17J show flow diagrams of themanufacturing method of the semiconductor device according to the eighthembodiment.

The wafer-fixing jig 50 is explained with reference to FIG. 16. Thewafer-fixing jig 50 is generally composed of a lower jig 51 and an upperjig 52. These lower jig 51 and upper jig 52 are constructed so as to becombinable. The combined lower and upper jigs are secured with a hook 59and thus the lower jig 51 and the upper jig 52 are unified.

The lower jig 51 is composed of metal (stainless) or ceramics, and awafer installation part 61 for installing the wafer 1 (same diameter asthe size of the diameter of the wafer W) is formed within the lower jig51. A protection member 54 for protecting the circuit-forming surface isarranged on the wafer installation part 61. The protection member 54consists of a porous protection member (rubber).

The lower vacuum hole 53 is formed in the lower jig 51. One end of thelower vacuum hole 53 is connected to the lower air joint formed on theside of the lower jig 51. A suction device not shown in the figure isconnected to the lower air joint 56. The other end of the lower vacuumhole 53 branches out into plural branches and opens up towards the waferinstallation part 61.

As the negative pressure is applied to the lower air joint 56 by drivingthe suction device, the wafer 1 installed to the wafer installation part61 is adsorbed by the lower vacuum hole 53. The wafer 1 is constructedso as to be held by the lower jig 51. A detent pin 55 is a pin used as apositioning pin when the lower jig is being combined with the upper jig52, and used to prevent rotation of each jigs 51 and 52 after havingbeen combined.

Plural escape grooves for dicing 58 are formed in the upper jig 52.These grooves are formed so that the dicing saw does not damage theupper jig 52, since the wafer 1 is subjected to the dicing process whilebeing held by the upper jig 52, as will be described later. An uppervacuum hole 57 is provided in the upper jig 52.

One end of the upper vacuum hole 57 is connected to an upper air joint60 formed on the side of the upper jig 52. A suction device not shown inthe figure is connected to the upper air joint 60. The other end of theupper vacuum hole 57 branches into several branches and opens downtowards the installation position of the wafer 1 (opens towards aposition between the dicing escape grooves 58).

As the negative pressure is applied to the upper air joint 60 by drivingthe suction device, the wafer 1 installed to the upper jig 52 isadsorbed by the upper vacuum hole 57. Wafer 1 is constructed so as to beheld by the upper jig 52. Here, the lower air joint 56 and the upper airjoint 60 are connected to independent suction device, and thus, thelower vacuum hole 53 and the upper vacuum hole 57 can independentlycarry out the suction process to the wafer 1.

Next, a method of manufacturing a semiconductor device using theconstructed wafer-fixing jig 50 is explained with reference to FIG. 17.

In this embodiment, the wafer 1 is installed to the lower jig 51 so thatthe back surface of the wafer 1 is facing up, and at the same time, thenegative pressure is applied to the lower vacuum hole 53 and the wafer 1is held by the lower jig 51, as shown in FIG. 17A. Here, the protectionmember 54 is applied to where the circuit-forming surface of the wafer 1contacts the lower jig 51, and thus circuit-forming surface is notdamaged through suction.

As shown in FIG. 17B, the back surface of the wafer 1 is subjected tothe back grind step while being held by the lower jig 51. The back grindprocess may be a mechanical process, a chemical process or any otherprocesses. At this point, the wafer 1 may be warped but this warping isnot significant since it is suctioned by the lower jig 51.

As shown in FIG. 17C, the lower jig 51 and the upper jig 52 arecombined, and the wafer 1 is sandwiched from the top and the bottom.Here, the wafer 1 is installed inside the wafer-fixing jig 50, and heldby each jigs 51, 52, and thus the suction process may be turned off. Ifthe suction process is turned on, the wafer 1 may be more securely heldand the warping may be more reliably prevented.

The wafer 1 is pulled out of the back grind device while beingsandwiched by each jigs 51, 52 (in a state installed inside thewafer-fixing jig 50), then proceeds to the die attach film 37application step. In this step, as the upper jig 52 is removed from thelower jig 51, the die attach film 37 is applied to the back surface ofthe wafer 1 using rollers not shown, as shown in FIG. 17D. If it isnecessary to apply heat depending on the type of the die attach film 37,heating mechanism may be provided on the table at the side of the devicefor setting the lower jig 51 (die attach mount device).

After the die attach mount process is completed, the upper jig 52 iscombined with the lower jig 51 again from the top and is in a state tobe transported. The wafer 1 is transported to the dicing device in thisstate and is installed to the table inside the dicing device.

As shown in FIG. 17F, the wafer-fixing jig 50 is turned upside down andset on the table inside the dicing device so that the circuit-formingsurface of the wafer 1 is facing upward. The suction process of theupper jig 52 is turned on, and the wafer 1 is held by the upper jig 52.When the wafer 1 is securely held by the upper jig 52, the lower jig 51is removed from the upper jig 52.

The wafer 1 is subjected to the dicing process in this state, as shownin FIG. 17G. The wafer 1 is cut to semiconductor elements 10. Upondicing, the wafer 1 is generally cut to pieces using a dicing saw, butbecause dicing escape grooves 58 are formed in a position correspondingto the dicing position of the upper jig 52, as stated above, the upperjig 52 will not be damaged by the dicing saw. Furthermore, since theopenings of the upper vacuum hole 57 are also provided opposite thesemiconductor elements 10, the semiconductor elements 10 are securelyheld by the upper jig 52 even if they are cut to pieces.

As shown in FIG. 17H, the lower jig 51 and the upper jig 52 are againcombined and the wafer 1 is transferred to the next step, the diebonder, and is installed. As the wafer-fixing jig 50 is installed on thetable of the die bonder, the negative pressure is applied to the uppervacuum hole 57 of the upper jig 52, and each of the semiconductorelements 10 is held by the upper jig 52. After the semiconductorelements 10 are securely held by the upper jig 52, the lower jig 51 isremoved from the upper jig 52.

The pick up/bonding process is carried out to semiconductor element 10individually in the die bonder, as shown in FIG. 17I and FIG. 17J. Whenthe semiconductor elements 10 are picked up, the suction of the upperjig 52 is turned off and only the suction of the collet 8 is turned on.

In this embodiment, since there is no need for peeling the semiconductorelement 10 from the tape, a special treatment of pushing up thesemiconductor from the under surface with a needle is unnecessary. Thus,it is possible to have zero damage to the thinned semiconductor element10 caused by the needle, and the damage of the semiconductor element 10is prevented.

In this embodiment, as stated above, when wafer 1 is subjected to theprocesses in each step, the wafer 1 is held either by the lower jig 51or the upper jig 52, and when being transported between each step, thewafer 1 is sandwiched between the lower jig 51 and the upper jig 52.Thus even with the thinned wafer 1, warping is not significant andperformance will improve. Furthermore, damage failure caused bytransportation will not arise.

The wafer-fixing jigs 20, 30, 40, and 50 used in each of the abovemanufacturing steps are all stackable one on top of the other, and theconventionally used dedicated carrier is no longer necessary whentransporting between steps. Thus, not only are the costs needed for theindirect tools reduced, but also there will be no damage when storingand taking out the jigs. By adding barcodes to the wafer-fixing jigs 20,30, 40, and 50, it is possible to manage information about the wafer 1.

According to the present invention, various advantages described belowmay be achieved.

According to one feature of the present invention, since thesemiconductor substrate is fixed to the semiconductor substrate jigwithout warps occurring in the semiconductor substrate, thesingularization step of the semiconductor substrate may be carried outsmoothly.

Further, according to another feature of the present invention, sincethe semiconductor substrate is fixed to the semiconductor substrate jigwithout warps occurring in the semiconductor substrate, the backgrinding step of the semiconductor substrate may be carried outsmoothly.

According to one feature of the present invention, it is possible toprevent bubbles from remaining between the semiconductor substrate andthe film, and thus the steps that follow can be conducted smoothly andat the same time damage of the semiconductor substrate due to theentering of bubbles may be prevented.

According to another feature of the present invention, it is possible toprevent bubbles from remaining between the semiconductor substrate andthe first adhesive tape, and because the semiconductor substrate can besecurely held by the semiconductor substrate jig in the back grind step,the back grind step can be conducted smoothly.

According to another feature of the present invention, after completingthe back grind step, the tape reapplication step may be conducted beforeor after the sigularization step. Thus, the degree of freedom indesigning steps of semiconductor manufacturing is enhanced.

According to another feature of the present invention, it is possible toprevent damage of the semiconductor substrate since the application stepdoes not exist, and at the same time there is little chance of bubblesentering between the semiconductor substrate and the adhesive tapeduring reapplication.

According to another feature of the present invention, the back grindstep can be conducted after the singularization step is completed. Withthis sequence, fragments caused at the edge portion of the semiconductorelement in the singularization step can be removed in the back grindstep. Thus, the strength of the semiconductor element is increased.

According to another feature of the present invention, it is possible toprevent bubbles from remaining between the semiconductor substrate andthe film because the annular member moves individually, graduallypressing the film to the semiconductor substrate from the centeroutward. Therefore, the steps that follow can be conducted smoothly anddamage to the semiconductor substrate due to the entering of bubbles maybe prevented.

According to another feature of the present invention, it is possible toprevent bubbles from remaining between the semiconductor substrate andthe first adhesive tape, and the state in which the semiconductorsubstrate is securely held by the semiconductor substrate jig ismaintained in the back grind step. Thus, the back grind step can beconducted smoothly.

According to another feature of the present invention, ultraviolet rayscan be irradiated through the semiconductor substrate jig to theadhesive having the property of ultraviolet curing, and the widely usedultraviolet curing type adhesives are used in the semiconductormanufacturing, thus the manufacturing cost of the semiconductor elementare reduced.

According to another feature of the present invention, even with athinned semiconductor substrate, the warping of the semiconductorsubstrate can be reliably prevented since the semiconductor substrate isheld by either the first jig or the second jig.

According to another feature of the present invention, the semiconductorsubstrate jig according to the present invention is used, and thus thewarping of the semiconductor is prevented when transporting thesemiconductor substrate between the first jig and the second jig, andtherefore, the breakage of the semiconductor substrate can be preventedthus enabling the subsequent semiconductor manufacturing steps to besmoothly conducted.

While the preferred embodiments of the present invention has beendescribed, it is to be understood that the present invention is notlimited to these embodiments, and variations and modifications may bemade without departing from the scope of the present invention.

1. A semiconductor substrate jig comprising: a first jig having a first suction mechanism sucking said semiconductor substrate; and a second jig having a second suction mechanism sucking said semiconductor substrate, said first and second jigs being removably constructed and independently sucking said semiconductor substrate. 